Detergent composition and method of preparing same

ABSTRACT

A detergent composition for automatic dishwashers is prepared by hydrating an alkali metal trimetaphosphate by reaction with a sodium hydroxide solution in the presence of an anionic wetting agent selected from sodium dodecyldiphenyl ether disulfonate or sodium 2-acetamido hexadecane-1-sulfonate or mixtures thereof. The hydrated tripolyphosphate is formulated with an alkali metal silicate, a bleach composition and sodium sulfate to form an excellent detergent composition.

United States Patent Gray et al. Feb. 19, 1974 [54] DETERGENTCOMPOSITION AND 3,248,330 4/1966 Feierstein 252/99 METHOD OF P IN SAME2,990,375 6/l96l Steinhauer et al..... 252/l38 3,344,174 9/1967Browssalian 252/161 x [75] Inventors: Frederic Wi m ay, Summlt;3,248,335 4/1966 T80! 61 al. 252/539 Peter Arthur Munger, MountainLakes, both of NJ. OTHER PUBLICATIONS Levitt Oils, Detergents andMaintenance Specialties, [73] Ass1gnee: Colgate-Palmolive Company, NewVOL 2, 1967, pages York, NY.

2 Filed; July 23 1971 Primary Examiner-Mayer Weinblatt Attorney, Agent,or FirmHerbert S. Sylvester; Mur- 1 PP 165,701 ray M. 0611; NormanBlumenkopf Related [1.8. Application Data [63] Continuation of Ser. N6.780,216, NOV. 29, 1968, [57] ABSTRACT abandoned. A detergent compositionfor automatic dishwashers is prepared by hydrating an alkali metaltrimetaphos- [52] US. Cl 252/99, 23/105, 23/106, phate by reaction witha sodium hydroxide solution in 23/ 107, 252/ 138, 252/539 the presenceof an anionic wetting agent selected from [5 l] l nt. Cl ld 7/ 5 6sodium dodecyldiphenyl ether disulfonate or sodium [58] Field of Search..252/99, 138, 539; 23/105, 2-acetamido hexadecane-l-sulfonate ormixtures 23/106, 107 thereof. The hydrated tripolyphosphate isformulated with an alkali metal silicate, a bleach composition and [56]References Cited sodium sulfate to form an excellent detergent compo-UNITED STATES PATENTS sition- 3,390,093 6/l968 Feierstein et al. 252/1384 Claims, N0 Drawings DETERGENT COMPOSITION AND METHOD OF PREPARING SAMEit must not tarnish silverware, nor allow spotting on glassware. Furtherit must not be corrosive to metals such as are used in automaticdishwashers; it must not cake during shelf-life nor gel within thewashing machine. The composition contains a bleach composition which haschlorine available for sanitizing the china, etc.; and this chlorinemust not be lost during shelf-life.

Clearly, meeting all of these criteria presents many problems since,frequently, in solving one problem, one 6 or another of the otherdifficultiesreoccur.

In dishwashing compounds generally, a detergent such as an alkali metalphosphate is emloyed. It is known that sodium tripolyphosphate, alkalimetal pyrophosphate or orthophosphate and sodium hexametaphosphate havebeen used. More recently it has been found that sodium tripolyphosphatehexahydrate is useful in such compositions. However, as frequentlyoccurs in preparing the hexahydrate from the tripolyphosphate ortrimetaphosphate, the reaction product contains excess water ofhydration which seriously and adversely affects certain characteristicsof the composition, such as chlorine stability and, of course, thecaking of the composition during shelf-life.

The commercially available hexahydrate of alkali metal tripolyphosphateis unsuitable for use in the detergent compositions of the presentinvention due, it is believed, to excess water of hydration whichimpairs the anti-caking characteristics and also impairs chlorinestability by causing the release of chlorine during shelf-life.

According to the present invention, a very suitable hexahydrate ofalkali metal tripolyphosphate is prepared, in situ, so to speak, whichwhen formulated into the dishwashing composition ensures the chlorinestability and markedly improves the anticaking properties duringshelf-life without impairing other desirable characteristics of thecomposition.

More specifically, an alkali metal silicate, in which the ratio of SiO/Na,O is from 1:2 to 1:32, in water, an alkali metal sulfate and ananionic wetting agent, such as sodium Z-acetamidohexadecane-l-sulfonate,or sodium dodecyldiphenyl ether disulfonate or mixtures thereof arecombined and mixed until a consistent form was obtained. An alkali metaltrimetaphosphate is added and the temperature raised to about 140F. Nexta 50 percent solution of sodium hydroxide was added. A vigorous reactionensued and the temperature of the reaction mass rose to about 220F withsubstantial fluffing or frothing. During the reaction period asubstantial amount of water vapor was evolved. After a short time thereaction subsided and the crumbly material which was nearly dry to thetouch was further dried by heating at l40F until a constant weight wasobtained. The product containing the alkali metal tripolyphosphatehexahydrate had a water content of about 21 percent (Ohaus MoistureAnalysis).

A bleach composition was prepared by dry mixing an alkali metaldichloroisocyanurate, an alkali metal sulfate and a portion of thehexahydrate of the alkali metal tripolyphosphate. About 8 parts byweight of the bleach composition is added to about 92 parts by weight ofthe tripolyphosphate hexahydrate. The proportion of thedichloroisocyanurate is such that there is provided in the finalcomposition about 1 percent available chlorine.

The dichloroisocyanurate is first mixed into the bleach compositionbefore mixing with the hexahydrate material so as to ensure a moreuniform distribution of the chlorine in the final composition.

The wetting agent which is added to the initial step for hydrating thetrimetaphosphate to the tripolyphosphate hexahydrate is, of course,present in the final composition and is initially added so that it has aconcentration in the final composition of from 0.5 to 2.5 percent. Itwas found also that when the pH value was near 10 there was no damage tooverglaze decoration on fine china.

It has been found that better overall results are obtained when thesodium 2-acetamidohexadecane-lsulfonate is used alone or in admixture inequal parts with sodium dodecyldiphenyl ether disulfonate.

The following specific example will illustrate the present invention:

sodium silicate (SiO,/Na,0 ratio 230 grams 122.35) water 160 gramssodium sulfate 12 grams sodium dodecyldiphenyl ether 8 grams disulfonatesodium Z-acetamidohexadecanel -sulfonate 8 grams sodium trimetaphosphate368 grams The above materials were thoroughly mixed to form a consistentfoam and heated to F. Then sodium hydroxide (50 percent solution) 192gm. heated to 140F was added to the above foam. In about one minute thetemperature rose to about 220F with marked fluffing or frothing withstrong evolution of water vapor during the reaction which was completedin about 3 minutes. The reaction mass was crumbly" and nearly dry to thetouch. It was then dried to a constant weight by heating to 140F. Thewater content was about 21 percent (Ohaus Moisture Analysis).

To 92 parts by weight of the sodium tripolyphosphate hexahydratematerial thus prepared were added 8 parts by weight of a bleachcomposition containing:

20% potassium dichloroisocyanurate 30% sodium tripolyphosphatehexahydrate 47.5% sodium sulfate 2.5% ultramarine blue if desired also,a very small amount of a suitable perfume (0.02 percent) may be added atthis stage.

The purpose of mixing the bleach composition and then adding it to thehexahydrate material is to ensure uniform distribution of thedichloroisocyanurate in the final composition.

The final dishwashing detergent has an approximate composition of:

58% phosphate (90% sodium tripolyphosphute hexahydrate) 14% sodiumsilicate (SiO,/Na,0 ratio 112.4) sodium sulfate 2% wetting agent 1.5%potassium dichloroisocyanurate (0.9% available chlorine) 19% waterbalance dyestuff and perfume The pH value of a 1 percent solution of thedetergent was approximately 10.2.

Subsequent dishwashing tests showed that the chlorine stability wasexcellent and that the other criteria concerning spotting of glassware,tarnishing of silverware, protection of overglaze decoration of finechina, cleaning, sanitizing, caking during shelf-life, gelling duringuse, and foaming were all excellent.

Although reference has been made to specific compounds and quantities inthe above description and in the appended claims, it will be understoodto those familiar with this art that equivalents are to be included bythe terminology used.

It will be apparent that changes and modifications of the variousfeatures described herein may be made without departing from the spiritand scope of the invention. it is therefore apparent that the foregoingdescription is by way of illustration of the invention rather thanlimitation thereof.

We claim:

1. A method for preparing a composition suitable for use in automaticdishwashing processes comprising preparing a pre-mixture of sodium orpotassium trimetaphosphate, water, sodium or potassium silicate having asilicon oxide to metal oxide ratio of from 1:2 to 123.2 and an amount ofa wetting agent to provide from 0.5 to 2.5 percent thereof in the finalcomposition, said wetting agent being selected from the group consistingof sodium dodecyl diphenyl ether disulfonate, sodiumZ-acetamidohexadecane-l-sulfonate and mixtures thereof heating saidpremixture to about C. and thereafter reacting same with an aqueoussolution of sufficient sodium hydroxide to form the correspondingtripolyphosphate hexahydrate in a substantially dry form containing noexcess moisture thereafter drying said reaction product at about 140C.to constant weight and subsequently mixing said reaction mixture withsodium or potassium dichloro isocyanurate.

2. A method as claimed in claim 1 wherein the wetting agent is sodiumdodecyldiphenyl ether disulfonate.

3. A method as claimed in claim 1 wherein the wetting agent is sodiumZ-acetamidohexadecane-lsulfonate.

4. A method as claimed in claim 1 wherein the dichloroisocyanurate ispotassium dichloroisocyanurate. i l

2. A method as claimed in claim 1 wherein the wetting agent is sodiumdodecyldiphenyl ether disulfonate.
 3. A method as claimed in claim 1wherein the wetting agent is sodium 2-acetamidohexadecane-1-sulfonate.4. A method as claimed in claim 1 wherein the dichloroisocyanurate ispotassium dichloroisocyanurate.